TY - GEN
T1 - The influence of confinement on the hydrodynamic characteristics of a cylindrical pillar within a microchannel
AU - O'Connor, John
AU - Punch, Jeff
AU - Jeffers, Nicholas
AU - Stafford, Jason
N1 - Publisher Copyright:
Copyright © 2015 by ASME.
PY - 2015
Y1 - 2015
N2 - Microfluidic cooling technologies for future electronic and photonic microsystems require more efficient flow configurations to improve heat transfer without a hydrodynamic penalty. Although conventional microchannel heat sinks are effective at dissipating large heat fluxes, their large pressure drops are a limiting design factor. There is some evidence in the literature that obstacles such as pillars placed in a microchannel can enhance downstream convective heat transfer with some increase in pressure drop. In this paper, measured head-loss coefficients are presented for a set of single microchannels of nominal hydraulic diameter 391μm and length 30mm, each containing a single, centrally-located cylindrical pillar covering a range of confinement ratios, b=0.1-0.7, over a Reynolds number range of 40-1900. The increase in head-loss due to the addition of the pillar ranged from 143%to 479%, compared to an open channel. To isolate the influence of the pillar, the head-loss contribution of the open channel was extracted from the data for each pillar configuration. The data was curve-fitted to a decaying power-law relationship. High coefficients of determination were recorded with low root mean squared errors, indicating good fits to the data. The data set was surface-fitted with a power law relationship using the Reynolds number based on the cylinder diameter. This was found to collapse the data well below a Reynolds number of 425 to an accuracy of ± 20%. Beyond this Reynolds number an inflection point was observed, indicating a change in flow regime similar to that of a cylinder in free flow. This paper gives an insight into the hydrodynamic behavior of a microchannel containing cylindrical pillars in a laminar flow regime, and provides a practical tool for determining the head-loss of a configuration that has been demonstrated to improve downstream heat transfer in microchannels.
AB - Microfluidic cooling technologies for future electronic and photonic microsystems require more efficient flow configurations to improve heat transfer without a hydrodynamic penalty. Although conventional microchannel heat sinks are effective at dissipating large heat fluxes, their large pressure drops are a limiting design factor. There is some evidence in the literature that obstacles such as pillars placed in a microchannel can enhance downstream convective heat transfer with some increase in pressure drop. In this paper, measured head-loss coefficients are presented for a set of single microchannels of nominal hydraulic diameter 391μm and length 30mm, each containing a single, centrally-located cylindrical pillar covering a range of confinement ratios, b=0.1-0.7, over a Reynolds number range of 40-1900. The increase in head-loss due to the addition of the pillar ranged from 143%to 479%, compared to an open channel. To isolate the influence of the pillar, the head-loss contribution of the open channel was extracted from the data for each pillar configuration. The data was curve-fitted to a decaying power-law relationship. High coefficients of determination were recorded with low root mean squared errors, indicating good fits to the data. The data set was surface-fitted with a power law relationship using the Reynolds number based on the cylinder diameter. This was found to collapse the data well below a Reynolds number of 425 to an accuracy of ± 20%. Beyond this Reynolds number an inflection point was observed, indicating a change in flow regime similar to that of a cylinder in free flow. This paper gives an insight into the hydrodynamic behavior of a microchannel containing cylindrical pillars in a laminar flow regime, and provides a practical tool for determining the head-loss of a configuration that has been demonstrated to improve downstream heat transfer in microchannels.
KW - Confinement ratio
KW - Cylinder
KW - Head-loss
KW - Microchannels
KW - Microfluidics
KW - Pillar
UR - http://www.scopus.com/inward/record.url?scp=84980010019&partnerID=8YFLogxK
U2 - 10.1115/ICNMM2015-48701
DO - 10.1115/ICNMM2015-48701
M3 - Conference contribution
AN - SCOPUS:84980010019
T3 - ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM 2015, collocated with the ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems
BT - ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM 2015, collocated with the ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems
PB - American Society of Mechanical Engineers
T2 - ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM 2015, collocated with the ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems
Y2 - 6 July 2015 through 9 July 2015
ER -